In the wedding cake section, there are a few recipes for 10” size, if I’m not mistaken, but just for particular cakes. For sure it’s in RHC. Incresing to 10” pans will require some experimentation with leavening. You wouldn’t want to adjust baking soda, but baking powder would likely be less than the direct 25% increase for 9—> 10” pans, becuase you want more strength, and BP weakens the cake structure. Keep in mind, also, that many TCB recipes are for 1-1/2” deep pans, so there will be add’l calculations to increase to a 10x2 inch pan. To go from 9” 1-1/2 to 9x2”, you’d increase a single layer by 33%, and then to put that in a 10x2, increase that figure by another 25%. 13x9x2 is about the same as two 9x2 layers, but you might find yourself in fancy leavening land again, so experiment and note what you did in the even of success or failure!

Oh! I think genoises are much more flexible! Julie will be able to answer for sure. There’s a thread around here about genoises—I think the pan just needs to be as full as it says for the recipe, and you’re good to go. So the % increases would be good, but you don’t have to worry about the leavening concerns.

Wait for a genoise expert, though, before you do anything based on my recollections!!!!!

There are several ways to calculate your increase in genoise batter. There are charts on p. 502-3 for classic and chocolate genoise, that convert a 1-egg base unit into any size pan.

Alternatively, you can go by pan volume. There’s a chart on p.455 of pan volumes. A single 9x2 pan has a capacity of 8.67 cups, while the 10” round has a capacity of 10.75 cups. So 10.75 / 8.67 = 1.24x. Multiply everything by 1.24 (or to make it easier, 1.25). In other words, increase the recipe by 25%. Do the same type of calculation for the sheet pan.